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        <h1>
          <div class="m-doc-include m-code m-inverted m-right-m m-text-right"><span class="cp">#include</span> <a class="cpf" href="bn__optional_8h.html">&lt;bn_optional.h&gt;</a></div>
          <div class="m-doc-template">template&lt;typename Type&gt;</div>
          <span class="m-breadcrumb"><a href="namespacebn.html">bn</a>::<wbr/></span>optional <span class="m-thin">class</span>
        </h1>
        <p><code>std::optional</code> like container.</p>
        <table class="m-table m-fullwidth m-flat">
          <thead>
            <tr><th colspan="2">Template parameters</th></tr>
          </thead>
          <tbody>
            <tr>
              <td style="width: 1%">Type</td>
              <td>Element type.</td>
            </tr>
          </tbody>
        </table>
        <nav class="m-block m-default">
          <h3>Contents</h3>
          <ul>
            <li>
              Reference
              <ul>
                <li><a href="#pub-types">Public types</a></li>
                <li><a href="#typeless-methods">Constructors, destructors, conversion operators</a></li>
                <li><a href="#pub-methods">Public functions</a></li>
                <li><a href="#friends">Friends</a></li>
              </ul>
            </li>
          </ul>
        </nav>
<p>It doesn&#x27;t throw exceptions. Instead, asserts are used to ensure valid usage.</p>
        <section id="pub-types">
          <h2><a href="#pub-types">Public types</a></h2>
          <dl class="m-doc">
            <dt id="ad7ec0bf9b6b3dc35aceba64a484eff55">
              using <a href="#ad7ec0bf9b6b3dc35aceba64a484eff55" class="m-doc-self">value_type</a> = Type
            </dt>
            <dd>Value type alias.</dd>
          </dl>
        </section>
        <section id="typeless-methods">
          <h2><a href="#typeless-methods">Constructors, destructors, conversion operators</a></h2>
          <dl class="m-doc">
            <dt id="a9ac2902b35699dfcf9caae5a3ea5bd64">
              <span class="m-doc-wrap-bumper"><a href="#a9ac2902b35699dfcf9caae5a3ea5bd64" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap">) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Default constructor.</dd>
            <dt id="a98115fef2ce681e343201f92d2c64820">
              <span class="m-doc-wrap-bumper"><a href="#a98115fef2ce681e343201f92d2c64820" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Null constructor.</dd>
            <dt>
              <span class="m-doc-wrap-bumper"><a href="#a95370a822973856beaaca686bba66dfd" class="m-doc">optional</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-flat m-info">defaulted</span> <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Copy constructor.</dd>
            <dt>
              <span class="m-doc-wrap-bumper"><a href="#a4ebb7e31ab57252b68e85dbb75773056" class="m-doc">optional</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Copy constructor.</dd>
            <dt>
              <span class="m-doc-wrap-bumper"><a href="#ab638ba6b28e1edb913b4d72450913879" class="m-doc">optional</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) <span class="m-label m-flat m-info">defaulted</span> <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Move constructor.</dd>
            <dt>
              <span class="m-doc-wrap-bumper"><a href="#a71be816a0a7b57f7eb239cbab53fa509" class="m-doc">optional</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Move constructor.</dd>
            <dt>
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper"><a href="#a51086913779342be350100a502d2a664" class="m-doc">optional</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp; other) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Copy constructor.</dd>
            <dt>
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper"><a href="#a7863ddce3222189aa3233fb177c3e022" class="m-doc">optional</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp;&amp; other) <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Move constructor.</dd>
            <dt>
              <span class="m-doc-wrap-bumper"><a href="#a8aa230e19b4a0610b0ad6112639fa5c6" class="m-doc">optional</a>(</span><span class="m-doc-wrap">const Type&amp; value) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Constructor.</dd>
            <dt>
              <span class="m-doc-wrap-bumper"><a href="#abb593b76a6e81ab1c9f5fd8bda1250e3" class="m-doc">optional</a>(</span><span class="m-doc-wrap">Type&amp;&amp; value) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Constructor.</dd>
            <dt id="a29af78251ad723f69c01408bdb6ffac9">
              <span class="m-doc-wrap-bumper"><a href="#a29af78251ad723f69c01408bdb6ffac9" class="m-doc-self">~optional</a>(</span><span class="m-doc-wrap">) <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Destructor.</dd>
            <dt id="ace369943543ee33837aa87d8cc3e7376">
              <span class="m-doc-wrap-bumper"><a href="#ace369943543ee33837aa87d8cc3e7376" class="m-doc-self">~optional</a>(</span><span class="m-doc-wrap">) <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Destructor.</dd>
            <dt id="a497d934e01997709bd0436e78177ec21">
              <span class="m-doc-wrap-bumper"><a href="#a497d934e01997709bd0436e78177ec21" class="m-doc-self">operator bool</a>(</span><span class="m-doc-wrap">) const <span class="m-label m-flat m-info">explicit</span>  <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Indicates if it contains a value or not.</dd>
          </dl>
        </section>
        <section id="pub-methods">
          <h2><a href="#pub-methods">Public functions</a></h2>
          <dl class="m-doc">
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#a90c19a4ad14d13b56f938e589eb22186" class="m-doc">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Null assignment operator.</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#a7efd6aca67004f78c2402a588947bd49" class="m-doc">operator=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-info">defaulted</span> <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Copy assignment operator.</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#af5ece09620042c1a26668a771044bee5" class="m-doc">operator=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Copy assignment operator.</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#afdeb9d147160e6d54d75eb9d30bf781e" class="m-doc">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-info">defaulted</span> <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Move assignment operator.</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#aee2d8d94218426208f5f1e2e34be085c" class="m-doc">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Move assignment operator.</dd>
            <dt>
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#a578b783fc0487e8aa008097f4ec614f0" class="m-doc">operator=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp; other) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Copy assignment operator.</dd>
            <dt>
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#ad321419db4d43ed54c44f9bfcedec1a6" class="m-doc">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp;&amp; other) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-primary">constexpr</span> <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>Move assignment operator.</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#adabca04ce85a43781b7f1d1da6a2d156" class="m-doc">operator=</a>(</span><span class="m-doc-wrap">const Type&amp; value) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Assignment operator.</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#a27ba4b09c6f5608ffebbb4c85489d4b2" class="m-doc">operator=</a>(</span><span class="m-doc-wrap">Type&amp;&amp; value) -&gt; <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Assignment operator.</dd>
            <dt id="ab6e721e32cb4e290c31f36345f8ac47a">
              <span class="m-doc-wrap-bumper">auto <a href="#ab6e721e32cb4e290c31f36345f8ac47a" class="m-doc-self">has_value</a>(</span><span class="m-doc-wrap">) const -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Indicates if it contains a value or not.</dd>
            <dt id="a75de95398f2ddcba2d7e322074500362">
              <span class="m-doc-wrap-bumper">auto <a href="#a75de95398f2ddcba2d7e322074500362" class="m-doc-self">get</a>(</span><span class="m-doc-wrap">) const -&gt; const Type* <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a const pointer to the contained value.</dd>
            <dt id="a0637b81f7ff4ec0f0c0666fd387267f4">
              <span class="m-doc-wrap-bumper">auto <a href="#a0637b81f7ff4ec0f0c0666fd387267f4" class="m-doc-self">get</a>(</span><span class="m-doc-wrap">) -&gt; Type* <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a pointer to the contained value.</dd>
            <dt id="a277ef53adf253ede281f41af400bb979">
              <span class="m-doc-wrap-bumper">auto <a href="#a277ef53adf253ede281f41af400bb979" class="m-doc-self">value</a>(</span><span class="m-doc-wrap">) const -&gt; const Type&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a const reference to the contained value.</dd>
            <dt id="a9461a00456575cb07a06f6f336ccd85c">
              <span class="m-doc-wrap-bumper">auto <a href="#a9461a00456575cb07a06f6f336ccd85c" class="m-doc-self">value</a>(</span><span class="m-doc-wrap">) -&gt; Type&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a reference to the contained value.</dd>
            <dt id="a46f41ef574a40cf8246124bc89c2e468">
              <span class="m-doc-wrap-bumper">auto <a href="#a46f41ef574a40cf8246124bc89c2e468" class="m-doc-self">value_or</a>(</span><span class="m-doc-wrap">const Type&amp; default_value) const -&gt; Type <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a copy of the contained value if this optional has one; otherwise it returns a copy of the given default value.</dd>
            <dt id="a33d2a2542ad2f1ab49094d70804e13df">
              <span class="m-doc-wrap-bumper">auto <a href="#a33d2a2542ad2f1ab49094d70804e13df" class="m-doc-self">value_or</a>(</span><span class="m-doc-wrap">Type&amp;&amp; default_value) const -&gt; Type <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a copy of the contained value if this optional has one; otherwise it returns a moved copy of the given default value.</dd>
            <dt id="a19da9f372af7812779a27fed691cc317">
              <span class="m-doc-wrap-bumper">auto <a href="#a19da9f372af7812779a27fed691cc317" class="m-doc-self">operator-&gt;</a>(</span><span class="m-doc-wrap">) const -&gt; const Type* <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a const pointer to the contained value.</dd>
            <dt id="aa7538841c0316d7cc807d56f9321a850">
              <span class="m-doc-wrap-bumper">auto <a href="#aa7538841c0316d7cc807d56f9321a850" class="m-doc-self">operator-&gt;</a>(</span><span class="m-doc-wrap">) -&gt; Type* <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a pointer to the contained value.</dd>
            <dt id="a112e38d69c6150f13828f36e465b0dc1">
              <span class="m-doc-wrap-bumper">auto <a href="#a112e38d69c6150f13828f36e465b0dc1" class="m-doc-self">operator*</a>(</span><span class="m-doc-wrap">) const -&gt; const Type&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a const reference to the contained value.</dd>
            <dt id="ad920d023f063b2761d25242a6082ae0d">
              <span class="m-doc-wrap-bumper">auto <a href="#ad920d023f063b2761d25242a6082ae0d" class="m-doc-self">operator*</a>(</span><span class="m-doc-wrap">) -&gt; Type&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Returns a reference to the contained value.</dd>
            <dt>
              <div class="m-doc-template">template&lt;typename... Args&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#a16751a08309d9fa8ea1dec1991342ee5" class="m-doc">emplace</a>(</span><span class="m-doc-wrap">Args &amp;&amp; ... args) -&gt; Type&amp; <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Constructs the contained value in-place.</dd>
            <dt id="a568b26fa0763db1e87fcf4b23f0c42c1">
              <span class="m-doc-wrap-bumper">void <a href="#a568b26fa0763db1e87fcf4b23f0c42c1" class="m-doc-self">reset</a>(</span><span class="m-doc-wrap">) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Disposes the contained value.</dd>
            <dt>
              <span class="m-doc-wrap-bumper">void <a href="#a9fbcb9af5175de0fd9e73a8c4c9d7fba" class="m-doc">swap</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Exchanges the contents of this optional with those of the other one.</dd>
          </dl>
        </section>
        <section id="friends">
          <h2><a href="#friends">Friends</a></h2>
          <dl class="m-doc">
            <dt>
              <span class="m-doc-wrap-bumper">void <a href="#a0b6e6c2a4b162be53a1ae0335bcd457d" class="m-doc">swap</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; b) <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Exchanges the contents of a optional with those of another one.</dd>
            <dt id="add8bd17b952e020bad573a577cb9b453">
              <span class="m-doc-wrap-bumper">auto <a href="#add8bd17b952e020bad573a577cb9b453" class="m-doc-self">operator==</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Equal operator.</dd>
            <dt id="a0bd42f6b5a20933aa24d728bc004dc0a">
              <span class="m-doc-wrap-bumper">auto <a href="#a0bd42f6b5a20933aa24d728bc004dc0a" class="m-doc-self">operator&lt;</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Less than operator.</dd>
            <dt id="a5231bf50f3059bfd11682c4f7d2de3b8">
              <span class="m-doc-wrap-bumper">auto <a href="#a5231bf50f3059bfd11682c4f7d2de3b8" class="m-doc-self">operator&gt;</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Greater than operator.</dd>
            <dt id="a59072f056f9f8f80aea032f762aa5af7">
              <span class="m-doc-wrap-bumper">auto <a href="#a59072f056f9f8f80aea032f762aa5af7" class="m-doc-self">operator&lt;=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Less than or equal operator.</dd>
            <dt id="ac51f8f5c6cbd0d0c5f762fa38ef5ebf8">
              <span class="m-doc-wrap-bumper">auto <a href="#ac51f8f5c6cbd0d0c5f762fa38ef5ebf8" class="m-doc-self">operator&gt;=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Greater than or equal operator.</dd>
            <dt id="afec6887fe7cb3897dae1c8f6435e71d1">
              <span class="m-doc-wrap-bumper">auto <a href="#afec6887fe7cb3897dae1c8f6435e71d1" class="m-doc-self">operator==</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              <a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Equal operator.</dd>
            <dt id="ac7f8599ceb20c2b6855767cc4bf4fe00">
              <span class="m-doc-wrap-bumper">auto <a href="#ac7f8599ceb20c2b6855767cc4bf4fe00" class="m-doc-self">operator!=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              <a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Not equal operator.</dd>
            <dt id="a8afde056d8da9110b9a56082a0fffb2c">
              <span class="m-doc-wrap-bumper">auto <a href="#a8afde056d8da9110b9a56082a0fffb2c" class="m-doc-self">operator&lt;</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;,
              <a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Less than operator.</dd>
            <dt id="ab6134f7d0c999b42e3880f77d778cb38">
              <span class="m-doc-wrap-bumper">auto <a href="#ab6134f7d0c999b42e3880f77d778cb38" class="m-doc-self">operator&gt;</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              <a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Greater than operator.</dd>
            <dt id="a71cead462c51d56f51aa75aa5ff2bf82">
              <span class="m-doc-wrap-bumper">auto <a href="#a71cead462c51d56f51aa75aa5ff2bf82" class="m-doc-self">operator&lt;=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              <a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Less than or equal operator.</dd>
            <dt id="a867433cf8f505dceb1d0132b90a90128">
              <span class="m-doc-wrap-bumper">auto <a href="#a867433cf8f505dceb1d0132b90a90128" class="m-doc-self">operator&gt;=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;,
              <a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Greater than or equal operator.</dd>
            <dt id="adbe45ca9c0634009d525da6263178797">
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#adbe45ca9c0634009d525da6263178797" class="m-doc-self">operator==</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const OtherType&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Equal operator.</dd>
            <dt id="ab88f49b769eccc89a7853b0d4a6b1a73">
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#ab88f49b769eccc89a7853b0d4a6b1a73" class="m-doc-self">operator&lt;</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const OtherType&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Less than operator.</dd>
            <dt id="a1de0f795e0ed1e81ce42654a596f288d">
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#a1de0f795e0ed1e81ce42654a596f288d" class="m-doc-self">operator&gt;</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const OtherType&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Greater than operator.</dd>
            <dt id="a7652807203a371a80b3204cb5696046c">
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#a7652807203a371a80b3204cb5696046c" class="m-doc-self">operator&lt;=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const OtherType&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Less than or equal operator.</dd>
            <dt id="a6eeb403992eafbb851e6e855fd638ee7">
              <div class="m-doc-template">template&lt;typename OtherType&gt;</div>
              <span class="m-doc-wrap-bumper">auto <a href="#a6eeb403992eafbb851e6e855fd638ee7" class="m-doc-self">operator&gt;=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              const OtherType&amp; b) -&gt; bool <span class="m-label m-flat m-primary">constexpr</span></span>
            </dt>
            <dd>Greater than or equal operator.</dd>
          </dl>
        </section>
        <section>
          <h2>Function documentation</h2>
          <section class="m-doc-details" id="a95370a822973856beaaca686bba66dfd"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a95370a822973856beaaca686bba66dfd" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-info">defaulted</span> <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Copy constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to copy.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="a4ebb7e31ab57252b68e85dbb75773056"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a4ebb7e31ab57252b68e85dbb75773056" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Copy constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to copy.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="ab638ba6b28e1edb913b4d72450913879"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#ab638ba6b28e1edb913b4d72450913879" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) <span class="m-label m-info">defaulted</span> <span class="m-label m-primary">constexpr</span> <span class="m-label m-success">noexcept</span></span></span>
            </h3>
            <p>Move constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to move.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="a71be816a0a7b57f7eb239cbab53fa509"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a71be816a0a7b57f7eb239cbab53fa509" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) <span class="m-label m-primary">constexpr</span> <span class="m-label m-success">noexcept</span></span></span>
            </h3>
            <p>Move constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to move.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="a51086913779342be350100a502d2a664"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
                template&lt;typename OtherType&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a51086913779342be350100a502d2a664" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp; other) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Copy constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>Different type optional to copy.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="a7863ddce3222189aa3233fb177c3e022"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
                template&lt;typename OtherType&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a7863ddce3222189aa3233fb177c3e022" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp;&amp; other) <span class="m-label m-primary">constexpr</span> <span class="m-label m-success">noexcept</span></span></span>
            </h3>
            <p>Move constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>Different type optional to move.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="a8aa230e19b4a0610b0ad6112639fa5c6"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a8aa230e19b4a0610b0ad6112639fa5c6" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap">const Type&amp; value) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">value</td>
                  <td>Value to copy.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="abb593b76a6e81ab1c9f5fd8bda1250e3"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"> bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#abb593b76a6e81ab1c9f5fd8bda1250e3" class="m-doc-self">optional</a>(</span><span class="m-doc-wrap">Type&amp;&amp; value) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Constructor.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">value</td>
                  <td>Value to move.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="a90c19a4ad14d13b56f938e589eb22186"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a90c19a4ad14d13b56f938e589eb22186" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1nullopt__t.html" class="m-doc">nullopt_<wbr />t</a>) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Null assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <tfoot>
                <tr>
                  <th style="width: 1%">Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="a7efd6aca67004f78c2402a588947bd49"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a7efd6aca67004f78c2402a588947bd49" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-info">defaulted</span> <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Copy assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to copy.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="af5ece09620042c1a26668a771044bee5"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#af5ece09620042c1a26668a771044bee5" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Copy assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to copy.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="afdeb9d147160e6d54d75eb9d30bf781e"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#afdeb9d147160e6d54d75eb9d30bf781e" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) <span class="m-label m-info">defaulted</span> <span class="m-label m-primary">constexpr</span> <span class="m-label m-success">noexcept</span></span></span>
            </h3>
            <p>Move assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to move.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="aee2d8d94218426208f5f1e2e34be085c"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#aee2d8d94218426208f5f1e2e34be085c" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp;&amp; other) <span class="m-label m-primary">constexpr</span> <span class="m-label m-success">noexcept</span></span></span>
            </h3>
            <p>Move assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to move.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="a578b783fc0487e8aa008097f4ec614f0"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
                template&lt;typename OtherType&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a578b783fc0487e8aa008097f4ec614f0" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap">const <a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp; other) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Copy assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>Different type optional to copy.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="ad321419db4d43ed54c44f9bfcedec1a6"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
                template&lt;typename OtherType&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#ad321419db4d43ed54c44f9bfcedec1a6" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&lt;OtherType&gt;&amp;&amp; other) <span class="m-label m-primary">constexpr</span> <span class="m-label m-success">noexcept</span></span></span>
            </h3>
            <p>Move assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>Different type optional to move.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="adabca04ce85a43781b7f1d1da6a2d156"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#adabca04ce85a43781b7f1d1da6a2d156" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap">const Type&amp; value) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">value</td>
                  <td>Value to copy.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="a27ba4b09c6f5608ffebbb4c85489d4b2"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a27ba4b09c6f5608ffebbb4c85489d4b2" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap">Type&amp;&amp; value) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Assignment operator.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">value</td>
                  <td>Value to move.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to this.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="a16751a08309d9fa8ea1dec1991342ee5"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
                template&lt;typename... Args&gt;
              </div>
              <span class="m-doc-wrap-bumper">Type&amp; bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a16751a08309d9fa8ea1dec1991342ee5" class="m-doc-self">emplace</a>(</span><span class="m-doc-wrap">Args &amp;&amp; ... args) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Constructs the contained value in-place.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">args</td>
                  <td>Parameters of the value to construct.</td>
                </tr>
              </tbody>
              <tfoot>
                <tr>
                  <th>Returns</th>
                  <td>Reference to the constructed value.</td>
                </tr>
              </tfoot>
            </table>
          </div></section>
          <section class="m-doc-details" id="a9fbcb9af5175de0fd9e73a8c4c9d7fba"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper">void bn::<wbr />optional&lt;Type&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a9fbcb9af5175de0fd9e73a8c4c9d7fba" class="m-doc-self">swap</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; other) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Exchanges the contents of this optional with those of the other one.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">other</td>
                  <td>optional to exchange the contents with.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
          <section class="m-doc-details" id="a0b6e6c2a4b162be53a1ae0335bcd457d"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename Type&gt;
              </div>
              <span class="m-doc-wrap-bumper">void </span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a0b6e6c2a4b162be53a1ae0335bcd457d" class="m-doc-self">swap</a>(</span><span class="m-doc-wrap"><a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; a,
              <a href="classbn_1_1optional.html" class="m-doc">optional</a>&amp; b) <span class="m-label m-primary">constexpr</span></span></span>
            </h3>
            <p>Exchanges the contents of a optional with those of another one.</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">a</td>
                  <td>First optional to exchange the contents with.</td>
                </tr>
                <tr>
                  <td>b</td>
                  <td>Second optional to exchange the contents with.</td>
                </tr>
              </tbody>
            </table>
          </div></section>
        </section>
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